Magnetic quantum oscillations of the longitudinal conductivity σzz in quasi-two-dimensional metals -: art. no. 195111

We derive an analytical expression for the longitudinal magnetoconductivity sigma(zz) in layered conductors in presence of a quantizing magnetic field perpendicular to the layers and for short-range in-plane impurity scattering in frame of the quantum transport theory. Our derivation points out quite unusual temperature and magnetic field dependences for Shubnikov-de Haas oscillations in the two-dimensional limit, i.e., (h) over bar omega(c)>4pit, where t is the interlayer hopping integral for electrons, and omega(c) is the cyclotron frequency. In particular, when (h) over bar omega(c)>4pit and (h) over bar omega(c)greater than or equal to2piGamma(mu) (here Gamma(mu) is the value of the imaginary part of the impurity self-energy at the chemical potential mu), a pseudo-gap centered on integer values of mu/(h) over bar omega(c) appears in the zero-temperature magnetoconductivity function sigma(zz)(mu/(h) over bar omega(c)). At low temperatures, this high-field regime is characterized by a thermally activated behavior of the conductivity minima (when chemical potential mu lies between Landau levels) in correspondence with the recent observation in the organic conductor beta"-(BEDT-TTF)(2)SF5CH2CF2SO3.